What are these holes for

[65TerrorCuda]

They're cast into the side but new rotors don't have em. 11 inch oldies off a 75 valiant, pictured next to 12 inch

 

[cudascott]

I think those were for balancing

 

[MoparMike1974]

I was going to say...either cooling or balancing.

 

[65TerrorCuda]

Thank you Scott and Mike. Kinda threw me off because it looks like those holes would weaken the hub

 

[jos51700]

Balance. The hallmark of a poor casting.